Software for OCR, OMR text and mark recognition wanted

We are an international management consultancy and are looking for OCR, OMR text and mark recognition software for a building materials supplier. Approximately 15% of incoming invoices are received by post, i.e. on paper, and approximately 85% are received by email as attachments. These attachments are usually in Adobe PDF format.

The software should meet the following requirements:

• Incoming invoices from various suppliers must be created in an internal invoice control system for further processing. To do this, certain data fields from the invoices must be transferred to this system
• Approximately 350,000 to 400,000 invoices are processed per year
• Invoices have different formats depending on the supplier (several hundred)
• Invoices usually arrive as PDF attachments to emails, less frequently on paper by fax or post
• On-premises preferred

Three to five software workstations are planned. Work is carried out in an MS Windows system landscape.